1. Field of the Invention
The present invention relates to a key lock-in prevention system and, more particularly, to a key lock-in prevention system for preventing an ignition key from being locked in a car after the driver gets out of the car with the key in a state of inserted in a key cylinder.
2. Description of the Relevant Art
Hitherto, there have been systems for preventing an ignition key from being locked in a car after the driver gets out of the car with the key inserted in a key cylinder. For example, systems have been known whereby a warning sound is generated for announcing a failure to remove an ignition key to the driver when the conditions for generating the warning sound are regarded as being met, that is, when a condition that the ignition key is in a state of inserted in the key cylinder (Condition 1), a condition that the driver's seat side door is open (Condition 2) and a condition that an ignition switch is in the off state (Condition 3), these three conditions being satisfied at the same time (e.g. Japanese Kokai 06-171467 and Japanese Kokai 09-249094).
By the way, when a driver starts an engine, usually, the driver opens the driver's seat side door to get onto the driver's seat, closes the door and inserts an ignition key into a key cylinder so as to turn the ignition key.
However, in summertime, since the temperature inside a car becomes extremely high, there are instances where a driver inserts an ignition key into a key cylinder and turns the ignition key so as to start an engine without closing the door. If such actions are tried, the above-described Conditions 1-3 are satisfied simultaneously at a point of time when the ignition key is inserted into the key cylinder, so that a warning sound is generated in a conventional key lock-in prevention system, resulting in an unpleasant feeling being given to the driver.